Questions and Answers about Dolphins

The
species living at Ocean World is bottlenose dolphins

Bottlenose dolphin
survival rates for the Sarasota population (the only one studied in enough detail)
is 0.961. This means that at least in the Sarasota Bay (and also
in captivity) the life expectancy (the average age they can be expected to reach)
is about 25 years. The maximum age (which only a few will reach)
is more than 40 years. Survival rates in other populations may be
different (the Indian River population in Eastern Florida has an estimated survival
rate of about 0.92 which means a life expectancy of about 12 years).

This issue was the subject of a paper by R.J Small and D.P. DeMaster:
"Survival of five species of captive marine mammals", published
in Marine Mammal Science, vol. 11(2): 209-226 (April 1995).
This study showed no significant differences between the survival rates of bottlenose
dolphins in captivity and in the wild (the Sarasota Bay population).

Dolphins
and whales out of water have two problems: heat and their own
weight.

Large
animals have low surface to volume ratios, so it is hard for them to cool themselves.
(This is why elephants and hippopotami often spend time in water.)
Also, whales are well insulated (blubber), which is good if they're in water,
but not if they're beached.
It's like having a winter coat in 70 degree weather- you'd overheat very quickly.

Also, a whale's body isn't designed to support its own weight- it relies on
water for support.
The larger whales will die from their own weight if they're beached long enough.

The
olfactory lobes in the cetacean brain are quite atrophied and non-existent in
some species.
In most cetaceans, the olfactory nerves and chemoreceptors have disappeared
or exist in a rudimentary form only.

The
answer for now should be "it is possible that they do...". Do
we have a chance to comprehend it some day? Will we be able to communicate
in return? These are not easy questions to answer and will not be answered
very soon. Studies and research on complex sounds exchanges between dolphins
are still under way. Sounds do not alone account for communication between
dolphins. Attitudes do also. Body talk (mammals
we said) is evident in many ways, as when a perturbed mother will hold a misbehaving
child on the bottom. The message is clearly "don't mess with me
and get back in line". Dolphins will also slap their tail
flukes on the surface as a kind of "hey stop that". Communications
does seem to take place on a much subtler level with posture and body contact.

Remember Dolphins are conscious breathers. Should they sleep and go unconscious
as we do they would simply suffocate or drown.
Sleeping Dolphins can be seen as resting, floating at the surface, with one
eye open.
After a time, they will close the one eye and open the other one.
They alternate like this throughout their entire nap.

Yes,
5 specific species live in fresh water, they are usually named after the river
they swim in such as the Amazon, the Yangzi Jiang, or the Ganges. They are Ganges
River Dolphin, Indus River Dolphin,Amazon River Dolphin, Franciscana, Chinese
River Dolphin

Dolphins have colonized
all oceans and seas of the planet, from polar
to tropical regions, true mammals they must get oxygen from
air and not from water such as fish, their infants are born underwater and must
be brought up to the surface immediately to survive. Another dolphin is
often present to help the mother when birth is taking place. Presence
or non presence of dolphins is a good indication of the state of the seas in
many parts of the world. Very common in some places twenty years
ago it has disappeared since. In other regions it is coming back
because of man efforts to de-pollute.

Climate or change in currents or sea temperature can also make dolphins disappear
or come back after many years, the most remarkable case of this is the Monterey
Bay in California where the Risso Dolphin reappeared in 1970 after a non presence
of 70 years.

Dolphins
seems to enjoy playing games with humans; they invent them if you don't.

We all heard of the famous stories about the dolphin rescues where a human is
pushed to the safety of the shore by dolphins.
Bottlenose dolphins seems to enjoy pushing items.
Dolphin species vary in their degree of curiosity and interaction with humans.
Individual dolphins vary to the same degree. Some species are very shy,
others will approach humans with great curiosity.
One solitary dolphin, interact with humans more than with any pod.
Jean Louise, a solo dolphin who lived in Brittany for many years, seemed to
enjoy swimming with people but did not allow physical contact.
If dolphins have spent time in captivity, they can become very use to people
touching them, riding along with them, etc.
But they also can become mildly aggressive; nipping, pushing, etc.

These are strong creatures with territorial interests.
It is also know of one dolphin in Italy that they didn't know what to do with
because he was so aggressive with humans and other dolphins.

Man is the dolphin greatest predator, more than 100,000 dolphins
die each year because of man, either in nets or for gastronomy (being eaten).
In the Pacific Tunas and Dolphins follow the same routes, for years they were
both captured in the nets aimed at the Tunas, the Dolphins were either drowned
or slaughtered.
From 200,000 to 500,000 dolphins were killed this way between 1960 and 1972.

Now under pressure of common citizens, new legislation, actions of nature and
wild life organizations, fishing industries in many countries have adopted new
nets so that dolphins can escape. Tuna is now guaranteed to be "Dolphin
Safe" in many regions of the globe (not all).
Despite ecologist actions Dolphins are still being served as meals in many parts
of Japan, and hundreds are massively slaughtered each year in the Faeroe Islands.
Pollution of rivers, seas, and oceans by man activities is also a great danger
for many species of dolphins, at the end of the food chain this mammal will
concentrate all the poisons and chemicals man does release in its habitat.

The second predator of Dolphin after man is the Shark, the
worst areas for these encounters are South Africa and Australia.

Finally the third greatest predator of Dolphins are .... Dolphins.
Orcas have the habit to eat fish, seals, infant whales and small dolphins.

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$2,500
Reward For Turning In A Dolphin Poacher

If you witness the
illegal capture, killing, or harassment of any marine mammal, such as bottlenose
dolphins, whales, and seals, you may be able to receive a reward of up to $2,500
from the federal government. To get a reward, the information you provide
has to lead to a conviction for a violation of the Marine Mammal Protection
Act. You can receive up to one-half of the fine that the government collects
based on your complaint.

If
you witness a fisherman shooting at dolphins to scare them away from his fishing
lines...

If a business imports fur seal skin wallets and is trying to get other businesses
to buy them for resale...

If a fishing boat allows much more than the legal limit of dolphins to get caught
in their nets...

All
dolphins and whales belong to the scientific order of Cetacean.
All cetacean are marine mammals that have adapted marvelously to water and lost
the faculty to come back on land again. Forever.

This order is divided into three suborders.
The toothed whales or Odontoceti which does include the killer
whales, the beluga whales, the dolphins, and the porpoises.
The Mysticeti which does include the blue whales and the gray
whales.
Finally the Archaeoceti which represent the extinct specie.

First cetacean are believed to have appeared 50 millions years ago
and colonized all seas when immersed lands were still nothing but a dense jungle.
The oldest fossil named "Pakicetus" was found in the eighties near
the Himalayan mountains on the Pakistani border.
Studies of this fossil have showed that it had still four limbs.
So it is clear that some mammals already living on land did return to the sea.
Why? It is not known.

This group was extinct about
15 millions years ago when the "squalodonte" or first cetacean (toothed
whales of which the dolphin descent) appeared.

Fossils found in Italy and
Germany along the Rhine river have identified the typical "squalodonte".
Legs are replaced by fins, one nostril has migrated on top of the head and has
become a blow hole, the body is long and narrow, long range of teeth have appeared.
It is already closer to the actual Orca than the older specie.
Modern forms of odontocetes appeared four to five million years ago.

The proper term is echolocation. As stated in previous answer Dolphins
can emit sounds from 1.5 to 11.0 kHz. Most echolocation takes place
in the range of 2.0-4.0 kHz for Tursiops truncatus, as does most other vocalizations,
whistles can go as high as 15 kHz. Sounds are believed to be emitted by the
"nasal sac", an area just behind the melon (the rounded region of
a dolphin's forehead). The melon itself might be used as a acoustic lens to
focus these sounds. Low frequencies are emitted to locate far away objects
as they travel far under water due to their long wave length. High frequencies
locate objects at close range with high precision but don't travel far due
to their short wave length. Dolphins can determine size, direction, speed,
distance, and some of the internal structure of any objects under water. A
female dolphin can detect that a swimming human female is pregnant (and will
often in reaction tend to protect her). As the produced wave of sounds bounce
off distant or close objects, the Dolphin receives in echo an acoustic "image"
that is send to the brain in the form of nerve impulses for interpretation
and action. Dolphin can detect a band of fish more than a hundred meters away.

Following are a few printed and electronic sources of information on dolphin
sonar,
Books:

Note:
Under the Marine Mammal Protection Act of 1972 (revised 1984) it is
illegal
to actively interacting with wild dolphins within United States boundaries,
This is not true in other parts of the world.

The Agriculture Department issued a proposals on Jan. 23, 1995
which details rules to protect dolphins at popular tourist attractions
that give people an opportunity to swim with the mammals.

There
are currently six legally registered dolphin-swim programs in the United States,
the USDA said, but animal welfare groups said the unofficial number is much
higher.

The
USDA suggests items, such as the rule that limits the people-to-dolphin ratio
at 3-to-1
and another that states dolphins can only spend two hours interacting with people
per day,
with a 10-hour rest period every 24 hours.
They also have limits on the size of the interaction area.

However you should never forget YOU are the visitor of the dolphin habitat,
so please respect them.